A Two Element Phased Array Coil Enabling Widespread Application of High Resolution MR Coronary Angiography

Abstract

Parallel imaging using sophisticated receiver coils has improved the clinical feasibility of magnetic resonance coronary angiography (MRCA). These techniques, however, are not readily available outside advanced imaging centers. Our custom-made 2-element phased array coil is readily and inexpensively assembled to address this limitation and enable the widespread application of MRCA. The 2-element phased array coil, comprised of two 4-inch, overlapping circular coils, is specifically designed for MRCA. We compare our prototype coil to two commercially available coils commonly used for MRCA. MRCA has been performed in 14 normal volunteers. Anatomic coverage, image quality, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) are calculated for each coil. The prototype coil has imaged 92.6% (125/135) of the segments compared to 83.7% (113/135) and 76.3% (103/135) (p = 0.002) using the surface coil and cardiac phased array coil, respectively. Excellent or good (grade 1-2) image quality has been attained in 85.9% (116/135) of all the coronary segments using the prototype coil compared to 77.0% (104/135) and 71 % (96/135) using the surface and cardiac phased array coils, respectively (p = 0.025). Overall, higher SNR and CNR have been achieved by the prototype coil compared to the surface and the cardiac phased array coils (SNR: 13.5 ± 5.3 vs 12.2 ± 3.7 vs 9.0 ± 3.1 and CNR: 7.5 ± 5.5 vs 6.2 ± 3.3 vs 3.7 ± 2.7, respectively). Compared to two commercially available coils, the 2-element phased array coil is associated with overall improved SNR and CNR and provides higher image quality with wider anatomic coverage.